"Liguy, thanks for your intellectual honesty and sharing it with us. Obviously you are a true empiricist, not stuck in the ideologies, which are passed on from one generation to the next...."
--Lol! Empricism is as much an ideology as any other set of assumptions about how the world works. (Of course, "ideology" has a variety of meanings, which we can't go into here.)
"doesn't the word 'empirical' mean 'of, or pertaining to the senses'?"
--'Empirical' is probably best understood as a view of the world in which conclusions are drawn and truth-claims made on the basis of observation rather than speculation or unexamined assumption. In terms of western science, 'empirical' is generally taken to mean measurable, reproducable results that can be verified by a third party. So while what one hears may be 'empirical' in the strict sense of being a form of observation, from the point of view of science (or its practical application as engineering), the fact that what one claims to hear cannot be independently verified makes it suspect as a basis for drawing firm conclusions about the question at hand--in this case the value of bi-wiring.
"Whether real or imagined, there is a difference."
--??? To what extent can we say that an imaginary difference is a real difference?
"My point on voices is meant to be absurd. All of our voices are produced by exact same material; the same human flesh. But they all sound different. So why is it absurd to some that some of us think cables sound different made of the same material?"
--Is your flesh my flesh? I think not! But the analogy doesn't work no matter how you frame it--a singer is a source, whereas cable is a carrier or transmitter, clearly an apples-and-oranges situation. A more apt analogy would consider various transport media; for example, would Pavarotti (or, to take someone who's voice isn't shot, Domingo) sound different in Boston's Symphony Hall than he would in the Academy of Music in Philly, and if so, would it be because the air in Boston is different from the air in Philadelphia, or because of other factors? (The source material is unchanged, but the carrier is different.)
--This is all in good fun, of course. But it is interesting to note that several folks here have raised complex epistemological issues, possibly without even realizing it. There's certainly no way to discuss those issues in a forum such as this, and in any case it's likely that many folks wouldn't even recognize these questions as either philosophical or open to discussion--folks from the U.S. anyway, with its aggressively positivist outlook. :-)
Cheers! . . . and good listening.